- Synthesis method for improving yield of 2, 5-difluorobenzaldehyde by adopting negative ion stabilizer
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The invention provides a synthesis method for increasing the yield of 2, 5-difluorobenzaldehyde by adopting a negative ion stabilizer, which comprises the following steps: S1, dissolving a raw material p-difluorobenzene in a solvent, adding the negative ion stabilizer into the mixed solution, and controlling the temperature at -70 to -40 DEG C, S2, adding n-butyllithium into the reaction solutionobtained in the step S1, carrying out heat preservation and stirring for 30 minutes, and controlling the temperature to be -70 to -40 DEG C, S3, dropwise adding N, N-dimethylformamide into the reaction solution of the element in S2, and determining the HPLC content of the raw materials in the reaction solution, and S4, carrying out aftertreatment quenching, extraction, acid regulation, concentration and rectification on the reaction solution obtained in the step S3 to obtain the product.Wherein the negative ion stabilizer in S1 is any one of pentamethyldiethylenetriamine, tetramethylethylenediamine and hexamethylphosphoramide, and the negative ion stabilizer is 0.7-1.4 molar equivalents of p-difluorobenzene. The complexing agent and the organic lithium reagent are subjected to complexing reaction, so that the stability of the lithium reagent is improved, the reaction yield is greatly improved, and industrial production is easy to realize.
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Paragraph 0022; 0046-0125
(2021/02/06)
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- A practical chemo-enzymatic approach to highly enantio-enriched cyanohydrin acetates
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The preparation of enantiopure cyanohydrin acetates via enzymatic hydrolysis has been investigated by screening a range of biocatalysts and reaction conditions. Enzymatic resolution has been optimised through variation of the hydrolase biocatalyst and reaction conditions leading to synthetically useful routes to enantiopure cyanohydrin acetates.
- Maguire, Nuala M.,Ford, Alan,Clarke, Sarah L.,Eccles, Kevin S.,Lawrence, Simon E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
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experimental part
p. 2144 - 2150
(2012/05/04)
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- Ethanobenzazepines
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Novel ethanobenzazepines, processes for the preparation thereof, and a method of alleviating pain utilizing compounds or compositions thereof are disclosed.
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